how to make the chip select high and low alternately in Spi

Hi friends,

I have written a SPI driver for 2 SPI slave devices.Can anybody help me out
how to make chipselect high and low alternately to communicate with other
SPI slave in user application.I am already using the same test application
spidev_test.c from SPI Documentation given by linux2.6.32.2

Thank you.